2. Units to be measured and calculated VoltageVoltsV or E ResistanceOhmsR or Ω Current AmpsI or A

3. There can be voltage without current but not current without voltage. There can be resistance without current or voltage. Current may or may not be present in a circuit. Current is through out the circuit.

4. Voltage is measured “across” a device in question. It is measured between point of different potential.

5. Resistance is measured “across” a device in question. R or Ω Voltage sources must be removed.

6. Current must be measured by “opening” the circuit and putting the meter in line or in “series” so that the current passes through the meter. A or I

7. COLOR CODING FOR RESISTORS

8. Ground or Common Unless otherwise noted the common lead of the meter is connected to the ground or common point of the circuit.

9. Ground or common is usually associated with the negative terminal of a DC power supply.

11. 2.8 Polarity of voltage drops page 60 The author is using electron flow. Electrons only flow in one directions.

12. Page 61 Polarity has nothing to do with Ohm’s Law: there are no negative voltages, currents, or resistance entered into any Ohm’s Law equations! There are other principles of electricity that do take polarity into account.

13. Units to be measured and calculated VoltageVoltsV or E ResistanceOhmsR or Ω Current AmpsI or A PowerWattW or P

14. 2.3 Power in electric circuits We wont be using this. Page 42

15. 2.3 Power in electric circuits We will be using this. Page 43 Watt W or P

18. Chapter 3 Home work Electrical Safety. Chapter 3 is important but not as important as chapter 5.

19. Chapter 4 SCIENTIFIC NOTATION AND METRIC PREFIXES

20. Chapter 5 will be next Subjects in blue not yet needed 5.1 What are ”series” and ”parallel” circuits?............ 129 5.2 Simple series circuits............................. 132 5.3 Simple parallel circuits........................... 139 5.4 Conductance.................................... 144 5.5 Power calculations............................... 146 5.6 Correct use of Ohm’s Law......................... 147 5.7 Component failure analysis....................... 149 5.8 Building simple resistor circuits.................... 155

21. Chapter 5 SERIES AND PARALLEL CIRCUITS Page 130

22. 5.2 Simple series circuits The first principle to understand about series circuits is that the amount of current is the same through any component in the circuit.

23. Page 134 The figure of 9 volts is a total quantity for the whole circuit, whereas the figures of 3k, 10k, and 5k are individual quantities for individual resistors.

24. Calculating I total by calculating R total first. R total = R1 + R2 + R3 R total = 3 kΩ + 10 kΩ + 5 kΩ R total = 18 kΩ

28. Page 137 Chapter 5

29. In class exercise

30. Vs=_____ R 1 =_____ R 2 =_____ R T =_____ I T =_____ Take the information given!

31. V S =_____ V R1 =_____ V R2 =_____

32. Vs= 12V R 1 = 1000Ω R 2 = 500Ω R T = 1500Ω I T =.008A Take the information given!

33. V S = 12V V R1 = 8V V R2 = 4V

35. Short Lab 4 Fig. 4.10 the Short Concept

36. Lab 4 Fig. 4.9 the Open Concept

37. 50 Vs

38. 50V/ 5kΩ +5kΩ = 5mA 5mA x 5kΩ = 25V R1 5mA x 5kΩ = 25V R2

40. Lab/Experiment 3 Ohm’s Law

41. Lab / Experiment 3 E AB in the experiment is a reference to page 32 where the terminals of the power supply are A and B. North Seattle lab has dual power supplies with an A and B source. The terminals are labeled + and -

42. PLOTTING OHM’S LAW Lab/ Experiment #3 Textbook page 53

43. PLOTTING OHM’S LAW

44. Textbook page 53

45. Lab / Experiment 3 page 41 By finding the reciprocal of the resistance, we have a measure of how well the material conducts electricity. The quantity is called conductance, has the symbol G, and is measured in siemens.

46. Lab / Experiment 3 page 41 Conductance, has the symbol G, and is measured in siemens.